A receiver tube for a hearing instrument receiver, the component that generates the sound heard by the user of the hearing instrument, connects the output of the receiver with the outside of the shell, conveying the sound from the receiver to the user's ear canal. Some receivers, such as the kind shown in U.S. Patent application Ser. No. 11/182,151, filed Jul. 15, 2005, and titled “Shock resistant and vibration isolated electroacoustical transducer assembly,” incorporated herein by reference, have an opening on one face of the unit from which sound exits and the receiver tube is positioned over that opening. To provide a secure attachment for such a receiver tube to the receiver, a retaining clamp may be provided to hold the receiver tube in place.